Sand martins at Skelde
In the summer, the little sand martin flies in and out of the nest holes in the steep slopes of Broagerland in the Sønderborg area.
Steep slopes and beautiful swallows
Every spring in Denmark we are visited by lots of beautiful swallows - and here one of them in particular is a festive cousin that you can enjoy the sight of quite closely in several places in the municipality. It is our smallest swallow, the sand martin, which returns every year to various steep slopes and cliffs all around our coasts to build nests and have a flock of chicks or two on their wings.
One of these places can be found on Broagerland, where along the beach south of Skeldekobbel you can see them flying in and out of their nest holes in the cliff. And there are usually many of them, as sand martins are colony breeders who like to build nests side by side in a kind of large bird community.
The sand martin are, as I said, the smallest of our three swallow species and thus only a small creature compared to both the barn swallow and the common house martin. It is a single-coloured matte brown on the entire upper side, somewhat a la liver pâté and light on the underside with a distinct brown chest band. The tail is slightly forked and the call of the sand martin sounds like scratching on sandpaper - try it if possible, if you've forgotten what it sounds like.
You find one of their breeding grounds by parking your bike or car at the parking site at Kragesand and then going left along the coast. Lean your neck back a little when you reach the slopes, because they build their nests at least a few metres height.
The flying mole
When the sand martin wants to build a nest, it starts by digging a long tunnel into the slope or bank of approx. 50-120 cm, almost like a mole. At the end of the entrance, it builds a nest made of straw and feathers, where it lays its 4-5 eggs at the beginning of May.
When you stand below the nest holes, you can see the swallows fly in and out to feed their young again and again. There is equality in the family, where both the female and the male bird share the work of hatching the eggs and finding food for the young. And the little birds are efficient parents who can usually manage to raise two litters in one summer if there are good conditions and enough food. Sand martins, like the other swallows, hunt insects in the air and the family collective often flies out together to look for food, as they like to fly together in large flocks in their hunt for flying insects and floating spiders.
In August/September, the chicks have left the nest and the sand martins begin to gather in large flocks in reed forests, where they go to sleep collectively before heading to their winter quarters in Central and West Africa.
A small bird with great power
During the sand martins breeding period from April to September, it is protected. So feel free to enjoy the sight of the beautiful animals, but leave the birds and their nests alone - then you are both nice and law-abiding. Precisely this protection regularly means that this small, fine bird can put an end to even large constructions and projects.
Sand martins do not only build nests in natural slopes, but also often in gravel pits, in artificial passages, such as e.g. pipes and the like and in the large piles of sand that often lie in connection with construction of buildings and of new roads etc. Therefore, it sometimes happens that you have to stop construction because the swallows have decided to settle in a pile of earth, as was the case, for example, during the construction of Esbjerg hospital a few years ago.
But as long as the sand martins stick to the beautiful slopes of Broagerland, you can't help but love the little liver paste-coloured flyer.
Have a really good trip out there!
Helle Tychsen Bojsen
Nature guide in Sønderborg Municipality
Nature guide Helle Tychsen Bojsen talks about the little sand martin, which builds its nest inside the cliff at Skelde.Photo:Dûrzan cîrano - wikimedia commons/Bo Bach